Separate units for flood or fog lighting and for spot lighting have been available for many years. Campers, policemen and firemen have used them without too much inconvenience because they can be hung from belts or otherwise and whichever unit is desired can be taken in hand readily when needed. However, it is apparent that a single unit having both capabilities in the space of one would be highly desirable in any case and particularly so when the lights are mounted on
Various schemes for accomplishing these ends have been proposed from time and time, and have involved placing two light sources within one envelope, each being mounted and arranged to provide one of the desired types of beams. Two examples are the U.S. Pat. No. 3,622,778 to Cibie and the U.S. Pat. No. 3,870,876 to Puyplat. Each of these patents discloses a generally similar dual driving light for automobiles in which a bulb is mounted centrally of a typical reflector, and a complete, separate second reflector is mounted within the confines of the first reflector and contains a second bulb. The second reflector is about one half the diameter of the first reflector and is located entirely to one side of the fore and aft axis of the first reflector. Consequently, the first reflector must be quite large or the second reflector must be rather small. Although this type of light performs its dual function satisfactorily, its design limitation and relative complexity detract from its desirability.
Another type of dual function light is represented by U.S. Pat. No. 1,148,101 to Kush and U.S. Pat. No. 3,759,084 to Plewka. Each has a first reflector with a first lamp and a second reflector mounted in spaced relation concentrically within the first reflector and provided with its own lamp which is spaced axially forward of the first lamp. In Kush, the idea is that the first lamp produces a dim light, the second lamp produces a medium light and the two lamps together produce a bright light. In Plewka the idea is that the second lamp produces the usual bright driving light and the first lamp illuminates the surrounding area to reduce the dazzling effect of the second lamp. In both cases, all of the rays are emitted in random array and produce a flood light effect and consequently there is no way to produce an alternative spot light effect.